Proton therapy employs focused beams to treat cancer, including prostate cancer. Supporters of the treatment argue that because the beams are tighter than conventional radiation therapy, it leads to fewer side effects.

However, the cost of proton therapy is about $48,000, roughly twice as much as other prostate treatments. And some scientists say the therapy is no more effective than conventional treatment -- and may have side effects of its own, including a higher rate of bowel problems.

OHSU hired a consultant two years ago to explore the pros and cons of building a center here. And it hopes to hire another one this year to do a more focused study. In late February, the Knight Cancer Center sent an administrator to a conference on the economics of proton therapy in Hampton, Virginia.

"We're definitely exploring the possibility," said Dr. Tomasz Beer, a prostate cancer expert and deputy director of the Institute, in February. "We've had meetings. It's not an easy decision." An OHSU spokesperson recently confirmed the university continues to consider it.

The university hopes to avoid the biggest hurdle around proton therapy: cost. The new generation of proton therapy centers are much smaller and cost $30 to $50 million. However, along with the smaller facility comes less capacity for patients, meaning the investment may not pay for itself as quickly.